While the first part is almost universally true, and the second is certainly understandable, the conclusion does not follow. Wishing for something does not make it true.

Real-life counterexamples

Even taken literally, the saying is not true. Many atheists have served in the military and have seen combat.

Pat Tillman

In July 2007, an ongoing investigation into the death of Cpl. Pat Tillman in Afghanistan uncovered the following anecdote about the incident in which he was killed:

"The chaplain said that O'Neal told him he was hugging the ground at Tillman's side, "crying out to God, help us. And Tillman says to him, `Would you shut your (expletive) mouth? God's not going to help you; you need to do something for yourself, you sniveling ...""